This study developed a simple, efficient and environmentally friendly fabrication method for surface-enhanced Raman spectroscopy (SERS) wipers for the rapid detection of individual and mixed pesticide residues in real samples. Non-toxic NaCl was used to overcome the electrostatic repulsion between cotton swabs and AgNPs in the decorating process. Cotton swabs containing NaCl molecules were immersed in a silver colloid to synthesize a silver-decorated cotton swab (SERS wiper). The fabrication conditions were optimized to improve the performance of the SERS wiper. Under optimal conditions, AgNPs were evenly and densely distributed on cotton swabs within 10 min of the synthesis process. Raman reporter molecules (Rhodamine 6G) were tested and good results were obtained: sensitivity was 2 × 10⁻⁹ M, RSDs were within 7.5%, showing good reproducibility and uniformity, and the storage life reached 32 days. Thiabendazole (TBZ), thiram, and their mixture in bitter gourds were successfully detected using the “wipe sampling-detection” method coupled with the SERS wipers. The detection limits of TBZ and thiram were 1 ng cm⁻². Multiple linear regression (MLR) and leave-one-out cross-validation methods were employed for quantitative analysis. The linear correlation coefficients of the predicted results and reference concentrations of individual and mixed pesticide residues in bitter gourds were all above 0.99, and the RMSEs were within 7 ng cm⁻². These results indicate that the SERS wipers combined with MLR models could accurately and quantitatively detect individual and mixed pesticide residues in real samples.

Microplastics (MP) and nanoplastics (NP) pollutions pose a rising environmental threat to humans and other living species, given their escalating presence in essential resources that living subjects ingest and/or inhale. Herein, to elucidate the potential health implications of MP/NP, we report for the first time by using label-free hyperspectral stimulated Raman scattering (SRS) imaging technique developed to quantitatively monitor the bioaccumulation and metabolic toxicity of MP/NP within live zebrafish larvae during their early developmental stages. Zebrafish embryos are exposed to environmentally related concentrations (3-60 μg/ml) of polystyrene (PS) beads with two typical sizes (2 μm and 50 nm). Zebrafish are administered isotope-tagged fatty acids through microinjection and dietary intake for in vivo tracking of lipid metabolism dynamics. In vivo 3D quantitative vibrational imaging of PS beads and intrinsic biomolecules across key zebrafish organs reveals that gut and liver are the primary target organs of MP/NP, while only 50 nm PS beads readily aggregate and adhere to the brain and blood vessels. The 50 nm PS beads are also found to induce more pronounced hepatic inflammatory response compared to 2 μm counterparts, characterized by increased biogenesis of lipid droplets and upregulation of arachidonic acid detected in zebrafish liver. Furthermore, Raman-tagged SRS imaging of fatty acids uncovers that MP/NP exposure significantly reduces yolk lipid utilization and promotes dietary lipid storage in zebrafish, possibly associated with developmental delays and more pronounced food dilution effects in zebrafish larvae exposed to 2 μm PS beads. The hyperspectral SRS imaging in this work shows that MP/NP exposure perturbs the development and lipid metabolism in zebrafish larvae, furthering the understanding of MP/NP ingestions and consequent toxicity in different organs in living species.

A feasibility study for non-invasive diabetic detection based on a low cost portable Raman spectrometer and urine surface-enhanced Raman spectroscopy (SERS) is presented. SERS of 41 urine samples (20 diabetic patients and 21 healthy volunteers) mixed with silver nanoparticles are measured by a self-developed portable Raman spectrometer (Hx-Spec) which is excited by a 785 nm diode laser and the spectrum range is 200–2700 cm ⁻¹ with a resolution (FWHM) of 6 cm ⁻¹ . By methods of principal components analysis and linear discriminant analysis, a diagnostic sensitivity of 85% and a specificity of 90.5% are achieved in separating diabetic samples from normal urine specimens. The corresponding receiver operating characteristic is 0.836, indicting the accuracy of the predictive model.

Since the nanomaterial has become one of the most popular topics, gold nanomaterials have always been a research hotspot. Gold nanostars (GNSs) as one of the formations of the gold nanoparticles has stepped on the stage due to its remarkable property. By using Turkevich method, Brust method, seeded growth method and seedless-based method with proper and specific modification, GNSs could be produced for different requirements. These GNSs present various properties under a proper modification: high physical and chemical stability, high biocompatibility and the ability of modification easily. Such enormous properties and the surface plasmon resonance of GNSs could be used for various-potential applications such as surface-enhanced Raman scattering (SERS) detection, in vivo diseases detection and therapy, drug delivery and release and so on. All these indicate that GNS is a valuable material in biological, phenomenological and optical researches.